(13)Carbon urea breath test is not as accurate as endoscopy to detect Helicobacter pylori after gastrectomy

Background: This study was conducted to determine (1) whether Helicobacter pylori infection decreases in conjunction with time elapsed after gastrecto my and (2) the diagnostic efficacy of C-13 urea breath test (UBT) for H pyl ori in patients after gastrectomy. Methods: From January 1997 to June 1998, 86 patients who had undergone gast rectomy and 180 patients with dyspepsia without gastrectomy were enrolled. A UBT for the analysis of excess (CO2)-C-13/(CO2)-C-12 ratio (ECR) was obta ined for each patient. Each patient also underwent endoscopy to obtain gast ric biopsies for histology and H pylori culture. The presence of H pylori b y either histology or culture served as the standard to test the efficacy o f UBT. The 86 patients with a prior gastrectomy were categorized into 3 sub groups (I, less than 1 year; II, 1 to 3 years; III, greater than 3 years), according to the interval between surgery and UBT. The initial H pylori sta tus of these 86 patients was determined by histologic evaluation of the res ected stomach. Results: At trial initiation, the postgastrectomy group had a lower H pylor i infection rate (52.3%) as compared with the dyspeptic control group (80%) . The initial H pylori status among subgroups I, II, and III was similar. T here was a trend for the presence of H pylori in the stomach to decrease wi th increasing time elapsed after surgery (I to III: 68.8%, 48.3%, 36%, resp ectively; p < 0.05). The maximum UBT sensitivity and specificity achieved w ere 82.2% and 87.8% in the gastrectomy group and 97.2% and 96.3% in the dys peptic group, with cutoff points of 2.5 and 4.0, respectively. Conclusion: The prevalence of H pylori diminishes with time elapsed after g astrectomy. UBT for detection of H pylori is more effective in patients wit hout prior gastrectomy than in patients who have undergone gastrectomy and is less effective than endoscopy for patients who have had a gastrectomy.